Integral of Composition Functions

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SUMMARY

The discussion focuses on solving integrals involving composition functions, specifically through variable substitution and trigonometric methods. The user attempted to substitute variables incorrectly, leading to confusion in integration. A recommended approach is to complete the square in the integrand, transforming it into the form \(\frac{dx}{\sqrt{A^2 - (B+Cx)^2}}\) and applying the substitution \(B+Cx = A \sin t\) for simplification. This method is essential for correctly evaluating complex integrals.

PREREQUISITES
  • Understanding of integral calculus
  • Familiarity with variable substitution techniques
  • Knowledge of trigonometric identities
  • Ability to complete the square in algebraic expressions
NEXT STEPS
  • Study the method of completing the square in integrals
  • Learn about trigonometric substitutions in calculus
  • Explore integration techniques for composite functions
  • Review examples of integrals involving square roots and trigonometric identities
USEFUL FOR

Students and educators in calculus, particularly those tackling integral problems involving composition functions and variable substitutions.

kuskus94
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Homework Statement



http://sphotos-h.ak.fbcdn.net/hphotos-ak-snc6/282312_368248176595083_1229435302_n.jpg

Homework Equations



To subtitute x into U, but that did not work.

The Attempt at a Solution



I have tried subtituting x into U like this :

http://sphotos-g.ak.fbcdn.net/hphotos-ak-snc7/578486_368249266594974_1874868606_n.jpg

The last two lines are my "goofing around" answer. :-p
 
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If you change variables, you have to change them all! You can't just leave some x's laying around. Now you have x=x(u) and you don't know how this integrates.

There is kind of a standard trick for any integral that looks like this, which is to first complete the square. What you want to do is to write the integrand into a form
[tex]\frac{dx}{\sqrt{A^2 - (B+Cx)^2}}[/tex]
and then do a trigonometric substitution [itex]B+Cx = A \sin t[/itex]
 

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